This invention relates to the art of cutting and more particularly to a locking safety utility knife.
In a standard utility knife, the blade is fixed within a body made in two halves held together by a screw. The blade may be replaced when dull by separating the halves and replacing or reversing the blade. Some knife bodies house extra blades as well.
Other knives have been proposed in which the blade can be moved fore and aft with respect to the body of the tool by various means, such as by turning a screw, or by squeezing an operating lever which advances the blade against the action of a retracting spring. In a prior patent, we provided a utility knife of the type having an operating lever with an adjusting screw which determined how far out of the handle the blade could extend when the lever was squeezed.
The present invention provides an improved mechanism for locking the blade in its variable retracted position, to prevent blade deployment until the locking mechanism is manually deactivated.